Rays and Sharks belong to the class of cartilaginous fishes(Chondrichthyes). Rays are classified into Batoidea, along with skates. Ray teeth becomeusually black, like shark teeth, as they fossilize. Ray teeth can be identified by the rectangular shape with ridges. Rays have a cartilaginousskeleton that rarely becomes fossilized. The teeth are common fossils because they are not made ??of cartilage.